Tensioning device for use in winding multiple strips upon a common mandrel



0 United States Patent [111 [72] Inventor Jean Gaudin [56] ReferencesCited Montigny les Cormeilles, France UNlTED STATES PATENTS 9f 333333,386,679 6/1968 Foulon 6. 226/195X l e Patented Dec. 15 1970 3,474,94510/1969 Takata 226/44X [73] Assignee Societe De Constructions MecaniquesDe Primary Examiner-Richard A. Schacher (j il Attorney- Karl Rath Creil,France a corporation of France Priority J11"e 19, 1968 ABSTRACT:Multiple strips are passed, On their way to a France common windingmandrel, in friction pressure contact with l 155514 the edges of amultiplicity of juxtaposed braking rings freely rotatively mounted upona drum forming part of a strip-tensioning device. The braking rings arespaced by pairs of inter- [54] vening spacing rings mounted upon thedrum to move freely 6 Cl 2 D axially but locked against rotationrelative thereto. The commg posite stack of alternate braking andspacing rings is held [52] [1.8. CI. 226/195; under resilient axialpressure by means of discrete ring-shaped 242/752 pneumatic expansionchambers interposed between each pair [51] Int. Cl. B65h 23/10 ofspacing rings, whereby to allow the braking rings to slip in- [50] Fieldof Search 226/195, dividually and to thereby maintain a desiredcloseness of the winding tensions of the strips.

PATENTEDBEB'I SIQYB 35471332 sum 2 or 2 II'AQL BATH ATTORNEY TENSIONINGDEVICE FOR USE IN WINDING MULTIPLE STRIPS UPON A COMMON'MANDREL Thepresent invention relates to a device for regulatingthe rate of windingor the winding tensions of multiple strips upon mandrel, in frictioncontact with' the outer edges of said rings and the rate of rotation ofthe rings is' controlled by friction brakes consisting of thin spacingrings located between said braking rings and arranged to-be rotatablewith said drum whilesliding freely axially thereon. An axial clampingforce acting on the composite stack of braking and spacing rings isprovided by an inflatable chamber located-at one of the extremities ofthe drum, the opposite end of which carries a fixed abutment.

In a device of the aforedescribed type, with'the strips being maintainedat an adequate friction pressure with the peripheral surface provided bythe outer edges of braking rings, that is, a pressure in excess of theaxial clamping pressure of the rings, there will occur a selectiveslippage between individual adjoining braking and spacing rings causedby differences in the translatory speeds of the strips, in such a manneras to maintain a desired closeness of the winding tensions of the stripsupon the common winding mandrel, as described andexplained in greaterdetail in the aforementioned copending application. f' I An importantobject of the present invention is'to ensure a more uniform distributionof the axial braking pressure between the braking and spacing rings in adevice of the referred to type, to further improve the constancy orcloseness of the winding tensions of the strips and in turn theeffectiveness and reliability of the winding apparatus.

The invention, both as to the foregoing and ancillary objects as well asnovel aspects thereof, will be better understood from thefollowingdetailed description of a preferred practical embodiment, taken inconjunction with the accompanying drawings forming part of thisspecification and in which:

FIG. 1 is an elevation, shown partly in section, of a multiplestrip-tensioning device constructed in'accprdancewith the principles ofthe invention and suitable'for use when winding multiple strips upon acommon mandrelj'and FIG. 2 is a fragmentary view to an enlarged scalemore clearly showing a part of FIG. 1. I

According to the invention, there is provided a tensioning device of thereferred to type for use when winding a plurality of strips on a commonarbor or mandrel, said device compris ing essentially a multiplicity ofjuxtaposed braking wheels or rings rotatively mounted upon a stationarydrum common thereto, pairs of friction spacing rings located betweenadjacent braking rings, to effect selective braking'thereof, and aplurality of discrete pneumatic expansion chambers located each betweena pair of braking rings and adapted to control the operation of thefriction or spacing rings.

According to a preferred embodiment of the invention, the drum istubular and connected with a sourceof supply of compressed air common toall the expansion chambers, in the manner as will become furtherapparent as the description proceeds.

In a strip-tensioning device of the foregoing type, the total axialclamping force is divided between the plurality of expansion chambers,wherefore the useful volume of each chamber need only be relativelysmall and it is possible to make the chambers not of an elastic or verydeformable material, such as natural or synthetic rubber or anequivalent plastic material, but rather of thin gauge metal of stainlesssteel or the like,

each chamber having two opposite walls deformable in the manner of adiaphragm under pressure of the compressed air introduced therein.

Apart from the functional advantages obtained by the provision ofdiscrete expansion chambers for each pair of adjoining braking rings,the chambers can be economically produced and each may advantageously beformed by two dish like members hermetically welded along their centralplane of union to provide a ring-shaped pressure chamber.

Referring more particularly to the drawings, in which like referencenumerals denote like parts in thedifferent views thereof, the deviceshown comprises a fixed drum 1 carried by supports or brackets 2 formingpart of the frame of the winding machine. The drum 1 is tubular, itsinternal cavity being marked 3 in the drawing FIG. 1. The extremities ofthe drum are hermetically closed by plugs 4 with numeral 5diagrammatically showing the union of a compressed air supply pipe 6coming out of the internal cavity 3. 1

The drum 1 carries a multiplicity of juxtaposed braking rings or wheels7 each rotatably mounted upon the drum by means of ball bearings 8. Apredetermined clearance c is provided between the sides of the wheels 7,this clearance being of the order of 0.2 mm., to allow the wheels toturn independently of each other. The sides 80, FIG. 2, of the hubs ofthe wheels 7 are machined to form annular friction surfaces and thewheels are furthermore provided with a peripheral friction lining 9,while the assembly or stack of wheels is held in place on the drum 1 bymeans of two end plates or abutments 20, FIG. 1, adjustable by means ofsecuring nuts 21 and lock nuts 22.

As more clearly shown in FIG. 2, there is provided at either side ofeach wheel 7 a thin spacing or friction ring 10 which, on its faceadjoining the corresponding friction surface 8a carries a'frictionlining 11. Each ring 10 carries or forms a lug or tab 12 which is'engaged in a longitudinal keyway 12 in the drum 1. On the face of therings 10 opposed to the lining 11 are secured cogs or the likeprojections 13 in appropriate number, to serve as centering means forthe ring-shaped expansion chambers 14. The keyway 12 may also serve as ameans to hold the inner races of the ball bearings 8.

Each expansion chamber 14 is formed of two annular dishlike members 15and 16 appropriately made of stamped stainless metal or steel of smallthickness and secured one to the other by hermetic welding along. theircentral plane of union. To each of the expansion chambers 14 isconnected an inner radial tube 17 which is in communication with acorresponding radial passage 18 drilled in the wall of the hollow drum1, the union between the tube "and the passage 18 being illustrateddiagrammatically at 19 in the drawing.

In operation, air compressed to the appropriate pressure, which may beadjustable, is fed through the pipe 6 into the internal cavity 3 of thedrum 1, whereby to penetrate through the passages 18 and the tubes 17into all the expansion chambers 14 in which the internal pressure isconsequently identical. Due to this pressure, the members 15 and 16 arelaterally deformed to a slight extent, sufficient nevertheless to spreadapart the two spacing rings 10 adjacent thereto and to apply thefriction linings 11 of these rings against the sides 8e of the hubs ofthe braking wheels or rings 7, in such a manner as to exert a brakingpressure. thereon, as the-rings are rotated by the strips 23, 24, FIG.1, being wound upon a common mandrel (not shown).

The braking force will be the same for all the wheels or rings 7,although there may be relative angular displacement between the wheelsowing to the different tensions of the strips passing thereover. Becauseof this arrangement there will be a uniform tightening of the turns ofthe strips in the coils formed upon the common-winding mandrel. As isunderstood, the drum 1 is positioned upstream" of the winder or mandreland the strips 23, 24, may be held at an adequate friction pressure withthe peripheral areas of the wheels 7 in any suitable manner (notshown),preferably by means of compressed air in the manner shown and describedby the copending application mentioned hereinabove, to which referenceis made for other details of the construction and operation of thetensioning device not specifically mentioned herein.

There is thus provided by the invention a multiple strip tensioningdevice of the referred to type which will ensure a constant brakingforce throughout between adjacent pairs of braking wheels and frictionrings by the action of the individual or discrete expansion chambers onefor each elemental braking device. As can be seen, whe e a singleinflatable or expansion chamber is used, as in -ie above-mentionedcopending application, acting upon the composite stack of alternatebraking and spacing rings, a relative rotation between certain of theadjacent rings of the stack will result in an increased pressure on theremaining rings, whereby to render it difficult to achieve a desireduniformity or closeness of the winding tension or tightness of the coilsbeing wound from the multiple strips.

On the other hand, the use of individual expansions chambers accordingtothe present invention, one for each cooperating pair of braking andfriction rings, ensures a constant friction or pressure for any of theelemental braking devices formed by said rings, independently of thecondition of the remaining devices, that is, whether at rest or inoperation as determined by the varying translatory speeds of the stripsbeing wound.

This, in turn results in an improved constancy or closeness of thewinding tensions of the individual strips 23, 24,...being wound.

As can be seen, the number of wheels 7 or braking rings advantageouslyexceeds the greatest number of strips to be wound, whereby each strip23, 24,...engages a plurality of wheels. As a consequence, the sametensioning device may be used in conjunction with multiple strips ofvarying numbers and/or widths. Besides, the strips may be applied to asuitable arc-straped portion of the outer cylindrical surface providedby the wheels 7 or linings 9, encompassing an angle of 180 and less, asshown in the aforementioned copending application.

in the foregoing the invention has been described in reference to apreferred exemplary device or embodiment. It will be evident, however,that variations and modifications, as well as the substitution ofequivalent parts or elements for those shown and described forillustration, may be made without departing from the broader scope andspirit of the invention. The specification and drawings are accordinglyto be regarded in an illustrative rather than in an restrictive sense.

lclaim:

l. A tensioning device for use in the winding of a plurality of stripsupon a common rotating mandrel comprising in combination:

l. a drum;

a multiplicity of juxtaposed braking rings freely rotatively mountedupon said drum for frictionally supporting a plurality of stripsapplied, on their way to said mandrel, to an arc-shaped fractionalportion of the outer surface formed by the edges of said rings;

3. pairs of spacing rings intervening between each two adjacent brakingrings;

4. means to lock said spacing rings against rotation but to allow offree axial movement thereof relative to said drum;

5. a pair of abutments fast on said drum, to confine the stack ofalternate braking and spacing rings therebetween; and

6. a plurality of ring-shaped pneumatic expansion chambers interposedeach between a pair of spacing rings, to apply axial pressure to saidstack.

2. A tensioning device as claimed in claim 1, said drum being in theform of a tube with means to seal the inside space thereof and to feedthereto a compressed gaseous medium, and means including a plurality ofradial ducts in said drum, to connect said chambers to said space.

3. A tensioning device as claimed in claim 1, said drum being in theform of a tube with means to seal the inside space thereof and to feedthereto a compressed gaseous medium, means including a plurality ofradial ducts in said drum, to connect said chambers to said space, andfriction linings applied to the adjoining sides of said spacing ringsand said braking rings.

4. A tensioning device as claimed in claim 1, each of said expansionchambers consisting of a pair of dish-shaped elastic members secured oneto the other along their central plane of union.

5. A tensioning device as claimed inclaim 1, said drum being in the formof a tube with means to hermetically seal the inside space thereof andto feed thereto a compressed gaseous medium, each of said expansionchambers consisting of a pair of dish-shaped elastic sheet metal memberssecured on to the other along their central plane of union, and aplurality of feeding tubes each extending from one of said chambers intoradial ducts in said drum, to connect said chambers with said space.

6. A tensioning device as claimed in claim 1, said drum being in theform of a tube with means to hermetically seal the inside space of saidtube and to feed thereto a compressed gaseous medium, said ringsprovided with central hubs on the opposite faces thereof, said spacingrings provided with friction lining on their sides facing said hubs, andmeans including a plurality of radial ducts in said drum, to connectsaid chambers to said space.

